Microplastics in Marine Environment: Occurrence, Distribution, and Extraction Methods in Marine Organisms

The pervasive presence of microplastics in marine environments has raised significant concerns. This review addresses the pressing issue of microplastic pollution in marine ecosystems and its potential implications for both the environment and human health. It outlines the current state of microplastic occurrence, distribution, and extraction methods within marine organisms. Microplastics have emerged as a significant environmental concern due to their harmful effects on ecosystems and their potential human health risks. These particles infiltrate marine environments through runoff and atmospheric deposition, ultimately contaminating beaches and posing threats to marine life. Despite the gravity of this issue, there has been limited research on the presence and distribution of microplastics in marine organisms. This review aims to bridge this knowledge gap by comprehensively examining the occurrence, distribution, and various extraction methods used to detect microplastics in marine organisms. It emphasizes the urgent need for targeted measures to manage microplastic pollution, highlights the significant role of human activities in contributing to this problem, and underscores the importance of reducing human-induced pollution to safeguard marine ecosystems. While this paper contributes to the understanding of microplastic pollution in marine environments and underscores the critical importance of taking action to protect marine organisms and preserve our oceans for future generations, it also emphasizes that, in effectively tackling the microplastic problem, a well-coordinated approach is essential, involving research initiatives, policy adjustments, public involvement, and innovative technologies. Crucially, prompt and resolute responses must exist to counteract the escalating peril posed by microplastics to the oceans and the global environment.

Effects of Climate Change on Marine Organisms

Global warming has become a global challenge having dire consequences on different aspects of the environment due to the melting of glaciers, excess carbon dioxide (CO2), and excess warming of water bodies among others. At a faster pace recently, climate change is affecting the marine environment, causing numerous alterations. Here, we address its consequences and the numerous alterations, which are more vital for researchers and global agencies to advocate more on why it’s essential to lessen the impact of climate change. Our review showed that the impacts of climate change are articulated at several stages of the marine ecosystem where it affects the inhabitants and their habitats. In response to climate change (ocean warming) marine species shift their latitudinal range to find suitable conditions leading to the redistribution of species. In addition, we found that growth reduction, sub-optimal behaviors, and reduced immune-competence of marine organisms, are as a result of thermal stress due to climate change. Also, the periodic changes in temperature above or below the optimum have a meditative reproductive effect on marine species, including fish. Finally, we discovered that due to higher water temperatures, several diseases showcase greater virulence in the sense that the marine species become less resistant to these diseases due to stress, increased virulence stimuli, or increased transmission.

PI3K/Akt/mTOR Signaling as Targets for Developing Anticancer Agents from Marine Organisms

The PI3K/Akt/mTOR signaling pathway is one of the most frequently dysregulated pathways in cancer.Targeting the PI3K-mediated pathway has been an important strategy for developing novel anticancer agents.In the past decades,more than 40 inhibitors of the PI3K/Akt/mTOR pathway have been developed at different clinical stages.Temsirolimus,everolimus,idelalisib,and copanlisib have been approved for clinical use by the Food and Drug Administration of the United States(FDA).However,the toxic-ity and drug resistance limit their efficiency in the treatment.Novel compounds with greater potency and selectivity,as well as im-proved therapeutic indices with reduced toxicity,are clearly required.Over the past three decades,a lot of bioactive ingredients with anticancer effects by affecting the PI3K-mediated pathways have been found from marine organisms.In the present mini-review,anticancer compounds from marine source that target the PI3K/Akt/mTOR signaling were reviewed.The molecular entities and their modes of action were presented.The marine compounds targeting special factors of the PI3K/Akt/mTOR were highlighted.

Recent Advances of Bioactive Marine Natural Products in Drug Discovery

Marine natural products(MNPs)are valuable resources for drug development.To date,17 drugs from marine sources are in clinical use,and 33 pharmaceutical compounds are in clinical trials.Presently the success of drug development from the marine resources is higher than the industry average.It is a feasible strategy to conduct the discovery of druglead compounds based on marine chemical ecology by fully exploiting the pharmacological potential of marine chemical defense matters.In the search for bioactive MNPs,our group has constructed a biological resources library including more than 1500 strains of fungi.Focusing on the strategy of Blue Drug Library,we have discovered a series of novel MNPs with abundant biological functions.Highly efficient and scalable total synthesis of(+)-aniduquinolone A(44)and pesimquinolone I(48)have been completed,which will facilitate access to sufficient quantities of candidates for in vivo pharmacological and toxicological studies.As a nucleoprotein(NP)inhibitor,QLA(75)possesses significant anti-influenza A virus(IAV)activities both in vitro and in vivo.CHNQD-00803(76)is a potent and selective AMP-activated kinase(AMPK)activator that can effectively inhibit metabolic disorders and metabolic dysfunction-associated steatohepatitis(MASH)progression.Moreover,we identified two new candidate molecules with potent anti-hepatocellular carcinoma effects.Particularly,as a natural guanine-nucleotide exchange factors for ADP-ribosylation factor GTPases(Arf-GEFs)inhibitor prodrug,CHNQD-01255(78)is qualified to be developed as a targeted candidate anticancer drug,which may be promising to apply for cancer immunotherapy.Hence,it is evident that MNPs play an important role in drug development.

Bioaccumulation and changes of trace metals over the last two decades in marine organisms from Guangdong coastal regions, South China

Trace metal(Cr, Ni, Cu, Zn, Cd and Pb) exposures, distribution and bioaccumulation were investigated in marine organisms from Guangdong coastal regions, South China. The results showed that all of the selected metals were observed in marine organisms with a predomination of Cu and Zn. The metal exposure levels exhibited obvious variations between species with the decreasing order of crab > shellfish > shrimp > fish. The higher metals enrichment seen in shellfish and crab species primarily attributed to their living habits and the higher sediment background values of trace metals. Endpoint bioaccumulation factor(BAFfd) was used to characterize the bioaccumulation potentials of marine organisms to trace metals, of which Cu and Zn were the most accumulated elements. The exposure of trace metals in the cultured organisms was far lower than those in wild marine organisms, which is probably due to the effect of growth dilution. Comparisons with previous studies demonstrated that the concentration profiles of most trace metals declined over the last one to two decades, except Cu, that increased indistinctively.

Marine biological injuries and their medical management:A narrative review

The marine environment can be extremely dangerous,and the harm caused by marine organisms when they contact the human body can be especially harmful,even deadly.Contact includes stings,bites,wounds,and consumption as food.In this article,the characteristics of the common marine biological injuries are summarized,the major marine organisms causing damage in China’s marine waters are described,and injury prevention and treatment methods are discussed.

An electrochemical study on the effects of marine fouling organisms on steel used in the sea

-Study on the effects of microorganism secretive membrane and covering layer of macrofouling organisms-Balanus reticulatus, Ostrea plicatula, Membranipora, Corophium and Algae on the corrosion of carbon steel and low-alloy steel by the determination of natural corrosive potentials, linear polarization and the polarization curver of dynamic potential scanning through an electrochemical equipment.The results show that the microorganism secretion membrane formed on sample surface has some protective role, during the initial period of exposure (about ten days). Then protective role decreases and corrosive rate increases with the lapse of immersion time. The protective role of some macrofouling organisms is shown in order as follows: Corophium> Balanus reticulatus>Algae>Membranipora>Ostrea plicatula.

Nontoxic Marine Anti-fouling Coating Containing Capsaicin

This paper summarizes a nontoxic Anti-fouling coating utilizing capsaicin as an anti-fouling agent. The capsaicin constituent used in the coating has a rating from about 100 000 to about 1 500 000 Scoville Heat Units. The capsaicin is mixed with a silicon dioxide and then solubilized into a free-flowing homogeneous liquid oleoresin composition by adding a solvent to increase solubility and facilitate mixing. The oleoresin capsaicin liquid solution is mixed with a suitable corrosion resistant epoxy resin, which is then mixed with a hardening catalyst and applied to the surface to be treated.

Statistical Study of Trace Elemental Concentrations in Major Types of Organisms from Typical Chinese Coastal Waters

Frequency distribution characteristics of trace elements Fe, Mn, Zn, Cu, Sr and Ba are studied for the marine organisms collected from typical Chinese coastal waters and compared with those of major elements Ca and Mg. Nearly all the distributions for trace elements in macroalgae, benthic molluscs, crustaceans, cephalopods and different tissues of fish ( muscle, liver and bone ) are found to show some degree of positive skewness, indicating a relatively large number of marine organisms with low concentrations for a particular element and only a few organisms with disproportionately high concentrations. Their distribution types are generally logarithmic normal distribution or nearly logarithmic normal distribution. Distribution of Ca is similar to that of trace elements, while Mg shows normal distribution. Average elemental concentrations of major types of organisms are calculated based on their frequency distributions.

Screening of Protease Inhibitory Activity in Aqueous Extracts of Marine Invertebrates from Cuban Coast

Protease inhibitors have been isolated from many variable sources;however, the need to identify and characterize new molecules has increased with the discovery of new therapeutic targets and the lack of specificity of already identified compounds with inhibitory activity. The goal of this work was to search for inhibitory activity against four proteolytic enzymes already recognized as therapeutic targets: human neutrophil elastase, dipeptidyl peptidase IV, subtilisin from Bacillus licheniformis and cathepsin K in selected marine invertebrates from the Caribbean Sea. A systematic screening was carried out with selected aqueous extracts belonging to 20 species from seven different phyla: Annelida, Bryozoa, Chordata, Cnidaria, Equinodermata, Mollusca and Porifera, all collected at the coast of Havana (Cuba). All extracts showing initial inhibitory activity were characterized in terms of IC50 values and specific inhibitory activity (SIA). Model enzymes were used in the case of human neutrophil elastase (porcine pancreatic elastase) and cathepsin K (papain) for the screening and all positive results were confirmed by testing toward the therapeutic targets. Ten extracts were identified showing inhibitory activity against human neutrophil elastase, for which the most promising values were obtained for Nerita peloronta. Only one extract, Bunodosoma granulifera, showed inhibitory activity against dipeptidyl peptidase IV with rather poor values of IC50 and SIA. Seven extracts showed inhibitory activity against B. licheniformis subtilisin with very good IC50 and SIA values for Lissodendorix isodyctialis, Cenchritis muricatus, and N. peloronta. Finally, eight extracts were positive for cathepsin K with almost similar parameters values among them. All these results confirmed the richness and potential of the marine invertebrate’s fauna and indicated new promising sources for the identification of natural compounds with potential application in therapeutics.

Pre and Post Effects Assessment of Marine Ranch Construction in Chlorophyll-a Concentration Using MODIS Data and a Web-Based Tool. A Case Study in Zhelin Bay, China

Chlorophyll-a (Chl-a) concentration in lakes can tell a lot about a lake’s water quality and ecosystem. It is a measure of the amount of algae growing in a waterbody and can be used to monitor the trophic condition of a waterbody. We studied the pre and post effects of marine ranch construction in Chl-a concentration in Zhelin Bay, Southern China using Normalized Difference Chlorophyll Index (NDCI) and a web-based tool (https://mapcoordinates.info/). We used 8 day composite MODIS image collections of 500 m resolution and randomly selected two stations to extract the chlorophyll-a concentration values through the web-based tool. We recorded the slight increase in NDCI values in all stations after the construction of marine ranch which is a good indicator of the marine organisms’ reproduction and survival.

Determining the Main Gas-generation Phase of Marine Organic Matters in Different Occurrence States using the Kinetic Method

This paper probes the determination of the main gas-generation phase of marine organic mattes using the kinetic method. The main gas-generation phase of marine organic matters was determined by coupling the gas generation yields and rates in geological history computed by the acquired kinetic parameters of typical marine organic matters （reservoir oil, residual bitumen, lowmaturity kerogen and residual kerogen） in both China and abroad and maturity by the EasyRo（%） method. Here, the main gas-generation phase was determined as Ro%=1.4%-2.4% for type Ⅰ kerogen, Ro%=1.5-3.0% for low-maturity type Ⅱ kerogen, Ro%=1.4-2.8% for residual kerogen, Ro%=1.5-3.2% for residual bitumen and Ro%=1.6-3.2% for reservoir oil cracking. The influences on the main gas-generation phase from the openness of the simulated system and the ＂dead line＂ of natural gas generation are also discussed. The results indicate that the openness of simulation system has a definite influence on computing the main gas-generation phase. The main gas-generation phase of type Ⅱ kerogen is Ro%=1.4-3.1% in an open system, which is earlier than that in a closed system. According to our results, the ＂dead line＂ of natural gas generation is determined as Ro=3.5 % for type Ⅰ kerogen, Ro=4.4-4.5% for type Ⅱ kerogen and Ro=4.6% for marine oil. Preliminary applications are presented taking the southwestern Tarim Basin as an example.

Environmental factors affecting regional differences and decadal variations in the buried flux of marine organic carbon in eastern shelf sea areas of China

To characterize environmental factors controlling decadal-scale variations in the buried flux of marine organic carbon(BFC_(m))in the eastern shelf sea areas of China(ECSS),four well preserved sediment cores collected from the central Yellow Sea mud(CYSM)area,the Yellow Sea Coastal Current(YSCC)area and the Changjiang River Estuary(CRE)were investigated in this study.In the CYSM,variations in BFC_(m) were found to be dependent on variations in primary productivity and to exhibit a cyclical trend possibly related to fluctuations in the Pacific Decadal Oscillation(PDO)and the East Asian winter monsoon index(EAWM).In the YSCC,BFC_(m) likewise depends on primary productivity.Prior to the 1950s,variations in BFC_(m) were similar to that of the EAWM.After the 1950s,BFC_(m) increased rapidly and exhibited maximum values in the surface layer,consistent with an increase in primary productivity caused by the input of terrestrial nutrients associated with China’s economic development.In the CRE,variations in BFC_(m) were affected by several competing factors making it difficult to identify clear relationships between variations in BFC_(m) and primary productivity.In contrast,long-term variability in BFC_(m) is more similar to changes in the Changjiang River sediment load.Thus,it is speculated that the construction of dams along the Changjiang River may be the main cause of variations in BFC_(m) in this area.Given the disproportionate effects of human activities on marine environments and decadal variations in BFC_(m) in the ECSS,careful attention should be paid to regional differences in organic carbon preservation and environmental changes lest estimates of these values be made imprecise or inaccurate.

Distribution and ecological evaluation of heavy metals in multi-medium of the Dongzhai Harbor

The distribution characteristics of heavy metals such as Cu, Zn, Pb, Cd, Hg. As in seawater, superficail sediments and several marine organisms of Dongzhai Harbor in Hainan were analyzed. Index methods of the single factor and geo-accumulation were used to assess the pollution degree of heavy metals. The results showed that the heavy metal levels in the seawater of Dongzhai Harbor accorded with the first category of the seawater except Pb, and were much lower than the fishery water quality standard; the concentration of the heavy metal in surface sediments did not exceed the national benchmark of the first-class of marine sediment quality basically, and the superficial sediments were essentially uncontaminated; the heavy metal content in wetland sediments was slightly higher than those in other typical mangrove wetland island of Hainan and marine sediments in Dongzhai Haibor, which indicated this area might has been affected by land-based pollution influence, and this should cause the attention of related departments; the heavy metal concentrations in marine organisms were up to the first category. All were not beyond the standard of non-environmental pollution aquatic products.

Kaili Biota: A Taphonomic Window on Diversification of Metazoans from the Basal Middle Cambrian: Guizhou, China

A Burgess Shale-type biota is, in part, characterized by a wide diversity of taxa and soft-part preservation. Each provides unique historical insights into early metazoan evolution. Among the more than 40 globally distributed biotas, the early Cambrian Chengjiang and Middle Cambrian Burgess-type biotas are the largest. The Kaili Biota, from the earliest Middle Cambrian of Guizhou, China, contains representatives of 110 metazoan genera belonging to 10 phyla. It contains many well-persevered soft-bodied specimens. This Chinese biota has become the third most taxonomically diverse Burgess Shale-type fauna. Because the Kaili Biota formed in an outer-shelf environment, its main faunal character is large numbers of eocrinoids and planktoic trilobites. The Kaili is younger than the Chengjiang Biota but older than the Canadian Burgess Shale Biota; it shares 30 genera with the Chengjiang and 38 genera with the Burgess Biota. The Kaili Biota displays a taphonomic window to the diversification and evolution of marine offshore organisms covering 5.13 million years between the Early and Middle Cambrian.

Polydeoxyribonucleotide: A promising skin anti-aging agent

Polydeoxyribonucleotide(PDRN) consists of DNA fragments with molecular weights ranging from 50 to 1 500 kDa,which are mainly extracted from the sperm cells of salmon trout or chum salmon. Many preclinical and clinical studies have demonstrated the properties of PDRN. These include anti-inflammatory, anti-apoptotic, antiosteoporotic, anti-melanogenetic, anti-allodynic, anti-osteonecrotic, bone regenerative, tissue damage preventive,anti-ulcerative, and wound healing properties, which are mediated by the activation of the adenosine A2Areceptor and salvage pathways. Moreover, PDRN promotes angiogenesis, cellular activity, collagen synthesis, soft tissue regeneration, and skin priming and revitalization and can be used to treat hyperpigmentation. Therefore, this review assessed the potential use of PDRN as an anti-aging agent for the skin.

The effect of iron on the preservation of organic carbon in marine sediments and its implications for carbon sequestration

Marine sediments are the most significant reservoir of organic carbon(OC)in Earth′s surface system.Iron,a crucial component of the marine biogeochemical cycle,has a considerable impact on marine ecology and carbon cycling.Understanding the effect of iron on the preservation of OC in marine sediments is essential for comprehending biogeochemical processes of carbon and climate change.This review summarizes the methods for characterizing the content and structure of iron-bound OC and explores the influencing mechanism of iron on OC preservation in marine sediments from two aspects:the selective preservation of OC by reactive iron minerals(iron oxides and iron sulfides)and iron redox processes.The selective preservation of sedimentary OC is influenced by different types of reactive iron minerals,OC reactivity,and functional groups.The iron redox process has dual effects on the preservation and degradation of OC.By considering sedimentary records of iron-bound OC across diverse marine environments,the role of iron in long-term preservation of OC and its significance for carbon sequestration are illustrated.Future research should focus on identifying effective methods for extracting reactive iron,the effect of diverse functional groups and marine sedimentary environments on the selective preservation of OC,and the mediation of microorganisms.Such work will help elucidate the influencing mechanisms of iron on the long-term burial and preservation of OC and explore its potential application in marine carbon sequestration to maximize its role in achieving carbon neutrality.

Carbon isotopic studies of individual lipids in organisms from the Nansha sea area, China

Carbon isotopes of individual lipids in typical organisms from the Nansha sea area were measured by the GC-IRMS analytical technique. δ13C values of saturated fatty acids in different organisms examined are from 25.6‰ to 29.7‰ with the average values ranging from 26.4‰ to 28.2‰ and the variance range of 1.8‰ between different organisms is also observed. Unsaturated fatty acids have heavy carbon isotopic compositions and the mean differences of 2.9‰–6.8‰ compared to the same carbon number saturated fatty acids. δ13C values of n-alkanes range from 27.5‰ to 29.7‰ and their mean values, ranging from 28.6‰ to 28.9‰, are very close in different organisms. The mean difference in δ13C between the saturated fatty acids and n-alkanes is only 1.5‰, indicating that they have similar biosynthetic pathways. The carbon isotopic variations between the different carbon-number lipids are mostly within ±2.0‰, reflecting that they experienced a biosynthetic process of the carbon chain elongation. At the same time, the carbon isotopic genetic relationships between the biological and sedimentary lipids are established by comparative studies of carbon isotopic compositions of individual lipids in organisms and sediments from the Nansha sea area, which provides scientific basis for carbon isotopic applied research of individual lipids.

Advances on marine-derived natural radioprotection compounds:historic development and future perspective

Natural extracts and compounds from marine resources have gained intensive scientific and industry attention for radio-protective activities in the past ten years.However,the marine-derived radioprotectants have been studied against UV-rays,gamma(y)-rays and X-rays for more than 30 years.This review aims to identify key marine-derived extracts/compounds and their modes of action studied for radioprotective activities from 1986 to 2019.A comprehensive survey was conducted to establish the trend in terms of the publications each year and the countries of origin.A total of 40 extracts and 34 natural compounds showing radioprotective activities against UV-rays,gamma(y)-rays and X-rays were identified from a range of marine plants and animals.These extracts and compounds are broadly categorized into polysaccharides,phlorotannins,carotenoids and mycosporine-like amino acids(MAAs).Macroalgae and microalgae were found to be the dominant sources of polysaccharides,phlorotannins and carotenoids.MAAs were mainly identified in algae,sponges,sea cucumber and corals that showed significant UV-absorbing activities.A number of radioprotective mechanisms were shown by these compounds,predominantly free radicals scavenging,inhibition of apoptosis,UV-ray absorption and DNA damage-repair signaling pathways.While these bio-discoveries warrant further investigation and development of radioprotective therapeutics,however,the lack of clinical studies is a major obstacle to be tackled in the future.

Biomaterials from the sea:Future building blocks for biomedical applications

Marine resources have tremendous potential for developing high-value biomaterials.The last decade has seen an increasing number of biomaterials that originate from marine organisms.This field is rapidly evolving.Marine biomaterials experience several periods of discovery and development ranging from coralline bone graft to polysaccharide-based biomaterials.The latter are represented by chitin and chitosan,marine-derived collagen,and composites of different organisms of marine origin.The diversity of marine natural products,their properties and applications are discussed thoroughly in the present review.These materials are easily available and possess excellent biocompatibility,biodegradability and potent bioactive characteristics.Important applications of marine biomaterials include medical applications,antimicrobial agents,drug delivery agents,anticoagulants,rehabilitation of diseases such as cardiovascular diseases,bone diseases and diabetes,as well as comestible,cosmetic and industrial applications.